Multiplex imaging to reveal the dynamics of MAVS-mediated control of Ebola virus replication in tissues.

Abstract

Abstract The RIG-I like receptor pathway that signals through the mitochondrial antiviral signaling protein (MAVS) is important in sensing RNA viruses, driving production of interferons, and inhibiting viral spread. How this signaling coordinates immune responses in tissues is incompletely understood. To understand the mechanisms of MAVS-mediated control, we examined the spatial relationship between EBOV antigen and cells in livers. C57BL/6J (B6) or MAVS−/− mice were inoculated intraperitoneally with 100 FFU of either wild-type (WT-EBOV) or mouse-adapted EBOV (MA-EBOV) with samples collected at 3 and 5 days post infection (dpi). This resulted in a spectrum of disease outcomes: complete survival (B6 WT-EBOV), weight loss and survival (B6 MA-EBOV and MAVS−/− WTEBOV) and 100% lethality (MAVS−/− MA-EBOV). Macrophage (MF), dendritic cell (DC) and T-Cell (TC) responses were examined by Opal-Plex, a multiplex staining method developed in house, combined with quantitative image analysis through object-based segmentation and spatial statistics. In B6 mice at 3 dpi, there was an increase in cellular recruitment of monocytes and CD8+ T-cells. An association between EBOV nucleoprotein (NP) and F4/80+ cells was observed in the survival phenotype and was especially prominent at 3 dpi. Further development of LysMCre MAVSfl/fl mice will determine if MAVS signaling in the macrophages is required for viral control to the macrophage compartment or if the phenotypes observed could have resulted from a bystander effect. This work will help to define dynamics of host control of viral dissemination and further define the relationship between tissue architecture and disease outcome. All studies were done with approval from the ICUC of the NIH/NIAID. Supported by The Intramural Program of the NIH/NIAID